The present invention relates to a high efficiency booster for use in applications where a gas turbine is the primary source of power, including hybrid automotive engines as well as other applications.
BACKGROUND ART
Boosters are currently used in applications where a gas turbine is the primary source of power, such as in hybrid automotive engines or in stationary plants for the purpose of increasing the power output of the gas turbine. As is known, a good power producing system is one that has reasonably high thermal efficiency consistent with economical, environmental, and other constraints. However, current technology does not allow the above-mentioned goals to be achieved in a typical four-cycle internal combustion engine, whether for an automotive engine or a stationary plant. This is because current technology provides only limited power output and thus decreased fuel efficiency.
One proposed solution for providing the desired fuel efficiency is through the development of a hybrid form of engine with multiple-fuel usage. This approach would likely require the use of reformulated gasoline, ethanol, methanol, alcohol, natural gas, a combination of fuels, or other fuels as potential primary sources of energy. Other energy sources such as electrical equipment (batteries, electric motors and generators) could optionally make a plant a hybrid power plant.
While hybrid vehicles have many advantages in comparison with conventional ones, employing the internal combustion engine in the hybrid vehicle, however, will not eliminate the problems peculiar to these engines. The primary problems associated with these engines include: pollution as a result of incomplete fuel combustion, the necessity of using only a special type of fuel, such as expensive gasoline or diesel fuels, comparable low thermal efficiency, dynamic loads resulting in more complicated suspension systems, and higher stress on some structural elements.
Electric vehicles have been proposed as a solution to the above problem. However, the major barrier to the immediate introduction of the electric vehicle has been limitations on current battery technology. In considering the efficiency of electric vehicles, the following factors must be taken into account, thermal efficiency of the power plant, losses of energy in transformers, electric power lines, and other losses in additional devices.
Employing an internal combustion engine in the hybrid vehicle would not solve the problems peculiar to these engines. The main problems are: pollution as a result of incomplete combustion of fuel, necessity of using a special type of fuelxe2x80x94expensive gasoline or diesel fuelxe2x80x94comparably low thermal efficiency, dynamic loads resulting in more complicated suspension systems, and higher stress on some structural elements. Another drawback is that a compressor utilized with the gas turbine typically uses a substantial portion of the turbine output power to operate, including as much as 50% or more. Such a configuration clearly could not meet the requirements of the Clean Air Act.
Another possible solution to the problem set forth above is contained in U.S. Pat. No. 4,578,995. The invention disclosed in the ""995 patent is particularly applicable to an automotive power plant or engine. It includes an electric motor with a drive shaft connected to a transmission, and a battery pack connected to the motor for driving the transmission at low speeds in urban areas to lessen the pollution. There is also an alternative power source disclosed for use with the motor.
The alternative power source includes an electric generator connected to the motor drive shaft, with power leads connected to the batteries and to the electric motor. The drive shaft is also coupled to an air compressor, which generates pressurized air that is directed into a combustion chamber. The hot gases from the combustion chamber are then passed at a high velocity through a conduit to a gas turbine with an impeller secured to the compressor shaft for transmitting a drive torque thereto and through the coupled motor drive shaft to the vehicle transmission. The turbine is primarily intended for use outside the urban area or for recharging the batteries. The turbine is preferably used when the vehicle is running on full load (for example, loaded and running with high speed). It is adapted to prolong the life of the vehicle batteries if the power source shifts from batteries to the gas turbine. The gas turbine disclosed in the ""995 patent has a comparable high thermal efficiency when it operates at full load. However, the efficiency of the gas turbine is drastically reduced at the lower loads than the rated capacity and thus, is inefficient.
It is thus an object of the present invention to provide a booster system for applications where a gas turbine is used as the primary source of power, which provides higher efficiency.
It is another object of the present invention to provide a hybrid vehicle or stationary plant utilizing a gas turbine that will significantly increase the peak cycle temperature and cycle pressure ratio and thereby improve the cycle thermal efficiency and ease of control of the unit under various loads.
It is yet another object of the present invention to provide a power producing system with high thermal efficiency and reduced emission or air pollution.
It is still another object of the present invention to provide a booster system to increase the efficiency of a compressor based system.
In accordance with the above and other objects of the present invention, an air booster system for use with a gas turbine to deliver compressed air to a combustion chamber is provided. The air booster system includes a first cylinder, having a first piston reciprocal therein, and a second cylinder having a second piston reciprocal therein. The first piston is connected to the second piston by a connecting rod such that the first piston and the second piston reciprocate together. The air booster system also includes a third cylinder having a third piston reciprocal therein and a fourth cylinder having a fourth piston reciprocal therein. The third piston is connected to the fourth piston by a connecting rod such that the third piston and the fourth piston reciprocate together. Each of the cylinders is in fluid communication with a compressor to receive preliminarily compressed air therefrom. The second cylinder and the fourth cylinder are also in communication with a reservoir to deliver highly compressed air thereto. The first cylinder is in fluid communication with the fourth cylinder, and the third cylinder is in fluid communication with the second cylinder.
These and other features of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawings and appended claims.